Last time I checked you couldn’t set a custom depth on the landscape, if that’s changed I’ll have to do some testing and make sure I can support it.
If you want to prevent shading behind translucency there’s a parameter called Transparency Strength that controls how much the lines draw through. Typically for water I’ll set it to 0.1, but if you set it to 0.0 it’ll remove it completely.
Also, with the other issue you were having try double checking it as there’s about six or eight very similarly named functions.